Prevent stuff like this:

mm/vmalloc.c: In function 'unmap_kernel_range':
mm/vmalloc.c:75: warning: unused variable 'start'

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch (as921) adds code to the show_regs() routine in i386 and x86_64
to print the contents of the debug registers along with all the others.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NNigel Cunningham <nigel@nigel.suspend2.net>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Following section mismatch warnings were reported by Andrey Borzenkov:

WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text:amd_init_mtrr from .text between 'mtrr_bp_init' (at offset 0x967a) and 'mtrr_attrib_to_str'
WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text:cyrix_init_mtrr from .text between 'mtrr_bp_init' (at offset 0x967f) and 'mtrr_attrib_to_str'
WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text:centaur_init_mtrr from .text between 'mtrr_bp_init' (at offset 0x9684) and 'mtrr_attrib_to_str'
WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text: from .text between 'get_mtrr_state' (at offset 0xa735) and 'generic_get_mtrr'
WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text: from .text between 'get_mtrr_state' (at offset 0xa749) and 'generic_get_mtrr'
WARNING: arch/i386/kernel/built-in.o - Section mismatch: reference to .init.text: from .text between 'get_mtrr_state' (at offset 0xa770) and 'generic_get_mtrr'

It was tracked down to a few functions missing __init tag.
Compile tested only.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 59f4e7d5 fixed machine rebooting
on Truxton's machine (when no keyboard was present).  But it broke it on
Lee's machine.

The patch reinstates the old (pre-59f4e7d5)
code and if that doesn't work out, try the new,
post-59f4e7d5 code instead.

Cc: Lee Garrett <lee-in-berlin@web.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Background:
 The MCE handler has several paths that it can take, depending on various
 conditions of the MCE status and the value of the 'tolerant' knob.  The
 exact semantics are not well defined and the code is a bit twisty.

Description:
 This patch makes the MCE handler's behavior more clear by documenting the
 behavior for various 'tolerant' levels.  It also fixes or enhances
 several small things in the handler.  Specifically:
     * If RIPV is set it is not safe to restart, so set the 'no way out'
       flag rather than the 'kill it' flag.
     * Don't panic() on correctable MCEs.
     * If the _OVER bit is set *and* the _UC bit is set (meaning possibly
       dropped uncorrected errors), set the 'no way out' flag.
     * Use EIPV for testing whether an app can be killed (SIGBUS) rather
       than RIPV.  According to docs, EIPV indicates that the error is
       related to the IP, while RIPV simply means the IP is valid to
       restart from.
     * Don't clear the MCi_STATUS registers until after the panic() path.
       This leaves the status bits set after the panic() so clever BIOSes
       can find them (and dumb BIOSes can do nothing).

 This patch also calls nonseekable_open() in mce_open (as suggested by akpm).

Result:
 Tolerant levels behave almost identically to how they always have, but
 not it's well defined.  There's a slightly higher chance of panic()ing
 when multiple errors happen (a good thing, IMHO).  If you take an MBE and
 panic(), the error status bits are not cleared.

Alternatives:
 None.

Testing:
 I used software to inject correctable and uncorrectable errors.  With
 tolerant = 3, the system usually survives.  With tolerant = 2, the system
 usually panic()s (PCC) but not always.  With tolerant = 1, the system
 always panic()s.  When the system panic()s, the BIOS is able to detect
 that the cause of death was an MC4.  I was not able to reproduce the
 case of a non-PCC error in userspace, with EIPV, with (tolerant < 3).
 That will be rare at best.
Signed-off-by: NTim Hockin <thockin@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Background:
 /dev/mcelog is typically polled manually.  This is less than optimal for
 situations where accurate accounting of MCEs is important.  Calling
 poll() on /dev/mcelog does not work.

Description:
 This patch adds support for poll() to /dev/mcelog.  This results in
 immediate wakeup of user apps whenever the poller finds MCEs.  Because
 the exception handler can not take any locks, it can not call the wakeup
 itself.  Instead, it uses a thread_info flag (TIF_MCE_NOTIFY) which is
 caught at the next return from interrupt or exit from idle, calling the
 mce_user_notify() routine.  This patch also disables the "fake panic"
 path of the mce_panic(), because it results in printk()s in the exception
 handler and crashy systems.

 This patch also does some small cleanup for essentially unused variables,
 and moves the user notification into the body of the poller, so it is
 only called once per poll, rather than once per CPU.

Result:
 Applications can now poll() on /dev/mcelog.  When an error is logged
 (whether through the poller or through an exception) the applications are
 woken up promptly.  This should not affect any previous behaviors.  If no
 MCEs are being logged, there is no overhead.

Alternatives:
 I considered simply supporting poll() through the poller and not using
 TIF_MCE_NOTIFY at all.  However, the time between an uncorrectable error
 happening and the user application being notified is *the*most* critical
 window for us.  Many uncorrectable errors can be logged to the network if
 given a chance.

 I also considered doing the MCE poll directly from the idle notifier, but
 decided that was overkill.

Testing:
 I used an error-injecting DIMM to create lots of correctable DRAM errors
 and verified that my user app is woken up in sync with the polling interval.
 I also used the northbridge to inject uncorrectable ECC errors, and
 verified (printk() to the rescue) that the notify routine is called and the
 user app does wake up.  I built with PREEMPT on and off, and verified
 that my machine survives MCEs.

[wli@holomorphy.com: build fix]
Signed-off-by: NTim Hockin <thockin@google.com>
Signed-off-by: NWilliam Irwin <bill.irwin@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Background:
 /dev/mcelog is a clear-on-read interface.  It is currently possible for
 multiple users to open and read() the device.  Users are protected from
 each other during any one read, but not across reads.

Description:
 This patch adds support for O_EXCL to /dev/mcelog.  If a user opens the
 device with O_EXCL, no other user may open the device (EBUSY).  Likewise,
 any user that tries to open the device with O_EXCL while another user has
 the device will fail (EBUSY).

Result:
 Applications can get exclusive access to /dev/mcelog.  Applications that
 do not care will be unchanged.

Alternatives:
 A simpler choice would be to only allow one open() at all, regardless of
 O_EXCL.

Testing:
 I wrote an application that opens /dev/mcelog with O_EXCL and observed
 that any other app that tried to open /dev/mcelog would fail until the
 exclusive app had closed the device.

Caveats:
 None.
Signed-off-by: NTim Hockin <thockin@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Insert the unclaimed MMCONFIG resources into the resource tree without the
IORESOURCE_BUSY flag during late initialization.  This allows the MMCONFIG
regions to be visible in the iomem resource tree without interfering with
other system resources that were discovered during PCI initialization.

[akpm@linux-foundation.org: nanofixes]
Signed-off-by: NAaron Durbin <adurbin@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we are in the emulated NUMA case, we need to make sure that all existing
apicid_to_node mappings that point to real node ID's now point to the
equivalent fake node ID's.

If we simply iterate over all apicid_to_node[] members for each node, we risk
remapping an entry if it shares a node ID with a real node.  Since apicid's
may not be consecutive, we're forced to create an automatic array of
apicid_to_node mappings and then copy it over once we have finished remapping
fake to real nodes.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For NUMA emulation, our SLIT should represent the true NUMA topology of the
system but our proximity domain to node ID mapping needs to reflect the
emulated state.

When NUMA emulation has successfully setup fake nodes on the system, a new
function, acpi_fake_nodes() is called.  This function determines the proximity
domain (_PXM) for each true node found on the system.  It then finds which
emulated nodes have been allocated on this true node as determined by its
starting address.  The node ID to PXM mapping is changed so that each fake
node ID points to the PXM of the true node that it is located on.

If the machine failed to register a SLIT, then we assume there is no special
requirement for emulated node affinity so we use the default LOCAL_DISTANCE,
which is newly exported to this code, as our measurement if the emulated nodes
appear in the same PXM.  Otherwise, we use REMOTE_DISTANCE.

PXM_INVAL and NID_INVAL are also exported to the ACPI header file so that we
can compare node_to_pxm() results in generic code (in this case, the SRAT
code).

Cc: Len Brown <lenb@kernel.org>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The logic in e820_find_active_regions() for determining the true active
regions for an e820 entry given a range of PFN's is needed for
e820_hole_size() as well.

e820_hole_size() is called from the NUMA emulation code to determine the
reserved area within an address range on a per-node basis.  Its logic should
duplicate that of finding active regions in an e820 entry because these are
the only true ranges we may register anyway.

[akpm@linux-foundation.org: cleanup]
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds caching of pgds and puds, pmds, pte.  That way we can avoid costly
zeroing and initialization of special mappings in the pgd.

A second quicklist is useful to separate out PGD handling.  We can carry the
initialized pgds over to the next process needing them.

Also clean up the pgd_list handling to use regular list macros.  There is no
need anymore to avoid the lru field.

Move the add/removal of the pgds to the pgdlist into the constructor /
destructor.  That way the implementation is congruent with i386.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: NWilliam Lee Irwin III <wli@holomorphy.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

timer_irq_works() needlessly became global.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Every file should include the headers containing the prototypes for its
global functions.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Constrain __supported_pte_mask and NX handling to just the PAE kernel.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hence remove its handling in the opposite case.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

.. and adjust documentation to properly reflect options that are
x86-64 specific.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Consolidate the three 32-bit system call entry points so that they all
treat registers in similar ways.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Too many remote cpu references due to /proc/stat.

On x86_64, with newer kernel versions, kstat_irqs is a bit of a problem.
On every call to kstat_irqs, the process brings in per-cpu data from all
online cpus.  Doing this for NR_IRQS, which is now 256 + 32 * NR_CPUS
results in (256+32*63) * 63 remote cpu references on a 64 cpu config.
/proc/stat is parsed by common commands like top, who etc, causing lots
of cacheline transfers

This statistic seems useless.  Other 'big iron' arches disable this.

AK: changed to remove for all SMP setups
AK: add comment
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix coding style, white space wreckage and remove unused code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hpet.h in asm-i386 and asm-x86_64 contain tons of duplicated stuff.
Consolidate into one shared header file.

AK: Fix i386 compilation with !X86_IO_APIC
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The hpet_rtc_interrupt handler still uses pt_regs. Fix it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove unused code and variables and do some codingstyle / whitespace
cleanups while at it.

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

xtime can be initialized including the cmos update from the generic
timekeeping code. Remove the arch specific implementation.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the generic cmos update function in kernel/time/ntp.c

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When making changes to x86_64 timers, I noticed that touching hpet.h triggered
an unreasonably large rebuild.  Untangling it from timex.h quiets the extra
rebuild quite a bit.

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove pit_interrupt_hook as it adds just an extra layer.
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current SMI detection logic in read_hpet_tsc() makes sure,
that when a SMI happens between the read of the HPET counter and
the read of the TSC, this wrong value is used for TSC calibration.

This is not the intention of the function. The comparison must ensure,
that we do _NOT_ use such a value.

Fix the check to use calibration values where delta of the two TSC reads
is smaller than a reasonable threshold.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The Intel PerfMon NMI watchdog reserves the first performance counter,
but uses the second one. Make it correctly reserve the second one.
Signed-off-by: NBjörn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is not fully softirq safe anyways.

Can't do a WARN_ON unfortunately because it could trigger in the
panic case.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With that an L3 cache is correctly reported in the cache information in /sys

With fixes from Andreas Herrmann and Dean Gaudet and Joachim Deguara
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This implements new vDSO for x86-64.  The concept is similar
to the existing vDSOs on i386 and PPC.  x86-64 has had static
vsyscalls before,  but these are not flexible enough anymore.

A vDSO is a ELF shared library supplied by the kernel that is mapped into
user address space.  The vDSO mapping is randomized for each process
for security reasons.

Doing this was needed for clock_gettime, because clock_gettime
always needs a syscall fallback and having one at a fixed
address would have made buffer overflow exploits too easy to write.

The vdso can be disabled with vdso=0

It currently includes a new gettimeofday implemention and optimized
clock_gettime(). The gettimeofday implementation is slightly faster
than the one in the old vsyscall.  clock_gettime is significantly faster
than the syscall for CLOCK_MONOTONIC and CLOCK_REALTIME.

The new calls are generally faster than the old vsyscall.

Advantages over the old x86-64 vsyscalls:
- Extensible
- Randomized
- Cleaner
- Easier to virtualize (the old static address range previously causes
overhead e.g. for Xen because it has to create special page tables for it)

Weak points:
- glibc support still to be written

The VM interface is partly based on Ingo Molnar's i386 version.

Includes compile fix from Joachim Deguara
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

gcc 4.3 supports a new __attribute__((__cold__)) to mark functions cold. Any
path directly leading to a call of this function will be unlikely. And gcc
will try to generate smaller code for the function itself.

Please use with care. The code generation advantage isn't large and in most
cases it is not worth uglifying code with this.

This patch marks some common error functions like panic(), printk()
as cold.  This will longer term make many unlikely()s unnecessary, although
we can keep them for now for older compilers.

BUG is not marked cold because there is currently no way to tell
gcc to mark a inline function told.

Also all __init and __exit functions are marked cold. With a non -Os
build this will tell the compiler to generate slightly smaller code
for them. I think it currently only uses less alignments for labels,
but that might change in the future.

One disadvantage over *likely() is that they cannot be easily instrumented
to verify them.

Another drawback is that only the latest gcc 4.3 snapshots support this.
Unfortunately we cannot detect this using the preprocessor. This means older
snapshots will fail now. I don't think that's a problem because they are
unreleased compilers that nobody should be using.

gcc also has a __hot__ attribute, but I don't see any sense in using
this in the kernel right now. But someday I hope gcc will be able
to use more aggressive optimizing for hot functions even in -Os,
if that happens it should be added.

Includes compile fix from Thomas Gleixner.

Cc: Jan Hubicka <jh@suse.cz>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>